DEAR DR. GOTT: I am a 73-year-old retired man in good physical condition. I work out at a gym three times a week. On the odd days, I stay active by walking, mowing, cutting brush, hiking, skiing, etc. I am seven pounds overweight BMI-wise, 172 pounds and 68 inches tall. I take 20 mg Lipitor to keep my cholesterol down (138 hg/dL). My HDL is 63, LDL 60. I also take Plavix for a suspected TIA eight years ago.
My situation is this: At the gym I warm up and stretch for 20 minutes. Then I do aerobics on the exercise machines (treadmill, bike, elliptical, etc.) for 45 minutes. I monitor my heart rate and try to keep it between 150 and 165 but occasionally I like to “sprint” which gets my heart rate up to 180. During all of these aerobic exercises, I feel strong with NO heart problem indicators — chest pain, dizziness, numbness, tunnel vision, blue lips and nails, or weak knees.
Question: Is there a limit to an exercise heart rate? Should I be concerned about going beyond 180? I am not cavalier about the danger of over stress but I do enjoy working out hard. But also, I would like to avoid the “E-Ticket” ride to the ER. I would be grateful for your advice or comments. Thank you.
DEAR READER: Wow! I must say you would be a tough act to follow were I to mimic your excise routine three days a week.
The body’s organs and muscles change in response to the demands placed on it. Over time the heart becomes more efficient at delivering the oxygen and fuel required by your muscles to maintain your higher level of performance. The skeletal muscles become more proficient at extracting oxygen from the bloodstream. When resting, the number of heart beats per minute will decrease, as can be documented over the years in well-trained athletes. A resting rate 10% above your normal level may, on occasion, indicate you may be over-training or ill. If this occurs, just don’t exercise that day. Give your body a needed rest.
The human heart rate (HHR) changes continuously. Before an individual can determine heart rate training zones, it will be necessary to determine your maximum heart rate. The simplest (but unfortunately least accurate) is the Estimated Maximum Heart Rate formula which is 220 minus your age. This applies to both men and women. In your case, 220 minus 73 equals 147 — a figure you clearly exceed. Then there’s the resting heart rate (RHR) that is determined by taking your pulse first thing in the morning before getting out of bed. Note that the need to urinate will increase your pulse rate. Should this situation arise, relieve yourself and go back to bed for a few minutes before proceeding. Record your readings for three days in a row and average those numbers out.
The Karvonen calculation devised by a Scandinavian physiologist is considered the gold standard for calculating an appropriate exercise rate. It essentially uses 220 minus your age and subtracting your resting heart rate. My advice is to speak with your physician to determine to what extent you should be exercising as well as what your target heart rate should be.
The need to exercise, eating nutritious meals and getting appropriate sleep on a regular basis cannot be underplayed. Keep up the good work.
Readers who would like related heart information can order my Health Report “Coronary Artery Disease” by sending a self-addressed, stamped number 10 envelope and a $2 US check or money order to my attention at P. O. Box 433, Lakeville, CT 06039. Be sure to mention the title when writing or print out an order form from my website www.AskDrGottMD.com.
